Nitroform derivative explosives



United States Patent 2,992,910 NITROFORM DERIVATIVE EXPLOSIVES Gustav Allan Wetterholm, Gyttorp, Sweden, assignor to v Nitroglycerin Aktiebolaget, Gyttorp, Sweden, a corporation of Sweden No Drawing. Filed Dec. 2, 1952, Ser. No. 323,694 Claims priority, application Sweden Dec. 6, 1951 '11 Claims. (Cl. 52-5) This invention relates to new valuable explosives on the basis of nitroform.

The compound trinitromethane or nitroform has been known from the end of the last century. In view of the fact that nitroform contains three nitro groups per carbon atom, it might a priori be supposed to be an effective explosive, but it has in spite hereof not been used as an explosive, for several reasons which render the compound itself practically unsuitable for this purpose.

Firstly, in the pure state nitroform is very dilficult to initiate and, when initiated, it is a very poor explosive with low brisance. In the solid state (melting point 56 C.) it is practically completely impossible to initiate nitroform and it cannot be made to detonate. Secondly, nitroform is a strong acid, comparable with nitric acid, and this acid nature, which according to Hantch (Ber. 32 (1899), 635) is to be referred to a pronounced mobility of the remaining hydrogen atom between the two forms is connected with many disadvantages. Further, nitroform is easily soluble in water, although not miscible therewith in all proportions (44.5 parts nitroform dissolve in 100 parts water) which is obviously not desirable in the case of an explosive and which contributes to make it hygroscopic. Finally, the stability of nitroform is unsatisfiactory for practical use. Even at such a low temperature as 30-35" C. technical, not recrystallized nitroform is decomposed, so that the concentration thereof decreases considerably (5-10%) in a :few days.

Although the compound nitroform itself, as indicated above, for several practical reasons is not suitable as an explosive, it has now according to the invention been found that certain derivatives thereof, which may be produced in difierent ways, are stable and efifective explosives. More particularly, it has been found in acoordance with this invention that compounds selected from the group consisting of mesityloxide nitroform, ditrinitroethyl urea and trinitroethyl melamine are especially effective explosive compositions.

As indicated above, the nitroform derivative explosives according to the invention may be used either alone or also mixed with other suitable explosives and other additions. Such mixed explosives may, in addition to the nitroform derivative, contain, for example, nitrated benzene derivatives, especially nitrated toluene and nitramine derivatives, organic nitrates, such as nitroglycerine and nitroglycol, and inorganic nitrates, such as ammonium nitrate, potassium, sodium and calcium nitrate.

Below a number of examples are given stating the composition of the explosives according to the invention and their solubility and other data concerning their properties, especially:

(1) Explosive characteristics, characterized by detonation velocity, small lead block crushing, lead block expansion (Trauzl);

Patented July 18, 1961 (2) Impact and friction test;

(3) Stability.

For determining said properties of the explosives the following investigation and testing methods have been used:

The detonation velocity has been determined photographically with a camera with rotating mirror, while using a 20 mm. string of explosive in a glass tube, at certain density. The small lead block test has been determined in mm. according to Hess for 35 -g. explosive, placed on two lead cylinders 30 x 40 mm. diameter and a 5 mm. thick iron plate on said cylinders. The net lead block expansion has been determined in according to Trauzl for 10 g. explosive. The impact sensitivity is normally stated as length of fall for 50% probability of initiation with 2 kg. falling weight. As all these tests have the character of standard tests for explosives a more detailed description is considered to be unnecessary.

The testing of stability has taken place by heating 1 g. explosive in a small bottle of alkali-proof glass (Pyrex glass) (diameter 20 mm., height 45 mm.) with outer connection through a capillary of 0.2 diameter and 40 length with a ground glass joint fitted tightly into the bottle. As measure of stability usually the time required for decomposition of 0.5% or 1% of the substance at a given temperature is stated. For comparison, it may be mentioned that this value for nitroglycerin is 27 hours at C., for penthrit 340 hours at 109 C. and 43 hours at 119 C., for trotyl 1000'hours at 132 C. and 6200 hours at 119 C., for hexagon 1000 hours at 132 C. Regarding the stability values stated, it is to be observed that they should not be considered as absolute values, since comparatively unimportant modifications in the purification process may result in considerable improvements of the stability. Further it is to be remarked that in case of long storage periods the volatility of the substance may have an influence upon the result, since it has not been possible to completely eliminate the volatility. In view hereof, the stability values given should be considered as values for the compounds in question.

The initiation has, with few exceptions, been efiected by means of a blasting cap No. 8. V

In the examples, the solubility is stated in percent corresponding to the number of grams of the substance in question which is soluble in 5g. water at 20 C.

7 Example 1 By the addition of 1 mol nitroformto 1 mol mesityl oxide a liquid compound of the composition H v V No, ,c -c H 0 n mesityl oxide nitroform having the structural formula:

having the solubility 0.06%, is obtained. This product had the following explosive characteristics: detonation velocity: the explosive was too diflicult to initiate for applying the photographical method, since this method does not permit an efiective enclosure. Small lead block test according to Hess was 12 mm, net lead block expansion ml. The stability corresponded to 0.5% decomposition after 16 hours at 80 C. and is consequently somewhat lower than in the case of nitroglycerin.

Example 2 With urea, also, a conversion with 2 mol trinitro ethanol takes place with the formation of substantially ditrinitroethyl urea having the structural formula:

(NO:)sCCHuHN-fi-NHCH2C(NO2)a This product is obtained in a yield of 80-85%. and has the solubility 0.08%. The raw product has a nitrogen content. of 29-31%. The. sensibility to impact corresponds in unphlegmatized state to 50% initiation for 300 mm., and. the melting point is 191 C. At the density of 1.45 the detonation velocity is 7400 m./sec., small lead block crushing 26 mm. and net lead. block expansion 460 ml. The stability is satisfactory and corresponds to a loss of weight of 1% after 700' hours at 80 C., or 53 hours at 100 C.

Example 3 Melamine or cyanuric triamide, C H N reacts with trinitro ethanol with substitution of 3 hydrogen atoms with the formation of trinitroethyl melamine, having the structural formula:

This compound, trinitroethyl melamine, has a solubility of 0.032%, a nitrogen content of 34.2% (-2.25 0 and 50% initiation by impact from 200 mm. The detonation. velocity for pressed bodies of the product of the density 1.54 is 770 m./sec., small lead block crushing 26 mm. and net lead block expansion 336 ml. The stability is satisfactory for practical purposes.

Example 4 A satisfactory mixed explosive which is insensible to impact may be produced by suspending in 60% by weight of molten trotyl at 75-80 C., 40% by weight of ditrinitroethyl urea. The mixture may easily be cast. This mixed explosive has the following properties: Detonation velocity 7200 m./ sec. (specific gravity 1.58), small lead block crushing 33 mm, net lead block expansion 306 mm. The impact sensitivity: insensible for a length of fall of 1 m. The stability is the same as that of the pure ditrinitroethyl urea.

Example 5 A plastic explosive of the following composition was prepared: 12.35% nitro glycol, 8. 1% monoglycerin acetin, 0.9% nitro cellulose, 30.0% ditrinitroethyl urea and 48.7% ammonium nitrate. This explosive had a density of 1.00 and the detonation velocity at this density was 6500 m./sec., small lead block test 28.5 mm, net lead block expansion 396 ml. and 50% detonation at 700 mm. length of fall.

According to their properties, the explosives according to the invention may be used in all the various fields in which explosives are employed; They may be components in civil explosives of plastic or powdered character, in cast or compressed militaryexplosives, in safety explosives with low impact sensitivity and in highly sensitive explosives. They may be employed for blasting caps and detonators, for detonating fuses and as coal mine explosives. Further, the explosives according to the invention may be employed for the production of high polymer explosives as a substitute for nitro cellulose, for example by subsequent polymerization of primary produced explo sives of unsaturated character.

I claim:

1. A new explosive which comprises as its principal active ingredient a compound selected from the group consisting of mesityloxide nitroform, ditrinitroethyl urea and trinitroethyl melamine.

2. A new explosive which comprises as its principal active ingredient mesityloxide nitroform.

3. A new explosive which consists essentially of mesityloxide nitroform in admixture with a nitrated benzene.

4. A new explosive which consists essentially of mesityloxide nitroform in admixture with an inorganic nitrate selectedfrom the group consisting of monium, potassium, sodium and calcium nitrates.

5. A new explosive which comprises as the principal active ingredient ditrinitroethyl urea.

6. A new explosive which consists essentially of ditrinitroethyl urea in admixture with a nitrated benzene.

7. A new explosive which consists essentially of ditrinitroethyl urea in admixture with an inorganic nitrate, selected from the group consisting of ammonium, potassium, sodium and calcium nitrates.

8. A new explosive which comprises as its principal active ingredient trinitroethyl melamine.

9. A new explosive which consists essentially of trinitro-- ethyl melamine in admixture with a nitrated benzene.

10. A new explosive which consists essentially of trinitroethyl melamine in admixture with an inorganic nitrate selected from the group consisting of ammonium, potassium, sodium and calcium nitrates.

11. As a new composition of matter ditrinitroethyl urea.

References Cited in the file of this patent UNITED STATES PATENTS 2,537,526 Hannum Jan. 9, 1951 2,602,732 Farr July 8, 1952 2,654,666 Taylor Oct. 6, 1953 OTHER REFERENCES Bios Final Report No. 709 (PB 47730'), The Production of Tetranitromethane etc. (prepared July 3, 1946'), released March 21, 1947, 13 pages, (Copy available Off. Tect. Service Dept. Commerce.) (Copy in 260-644.)

, Schultheiss: Bios Report (PB-91741), Pt. I, Report on Work in Connection With Explosives, December 1945, 11 pp. (Copy available in 260-644.) 

1. A NEW EXPLOSIVE WHICH COMPRISES AS ITS PRINCIPAL ACTIVE INGREDIENT A COMPOUND SELECTED FROM THE GROUP CONSISTING OF MESITYLOXIDE NITROFORM, DITRIMITROETHYL UREA AND TRINITROETHYL MELAMINE. 